The present invention relates in general to cooling electronic systems. In particular, the present invention relates to augmenting air cooling of electronic systems using a cooling fluid to cool air entering the electronics system, and to remove a portion of the heat produced by the electronics system.
As is known, the power dissipation of integrated circuit chips, and assemblies containing integrated circuit chips, continues to increase. Increased power dissipation is driven by factors such as increases in processor performance and clock speed, and increases in the number of devices per integrated circuit. Increases in circuit, module, and system power dissipation pose cooling challenges at each level of assembly. In particular, in air cooled systems having constant inlet air temperature, increased system level power dissipation results in increased airflow requirements, in order to maintain desired device temperatures.
Many server applications consist of frames or racks, into which a number of electronics drawers are inserted. Each drawer may contain, for example, one or more processors, memory, one or more nonvolatile storage devices (such as a hard disk drive or HDD), one or more power supplies, etc. Each drawer may be individually removable, providing access to the drawer components for repair and maintenance. Such systems may further include one or more fans or air moving devices in or on each drawer, for the purpose of drawing ambient air into the frame, over the drawer components, and exhausting heated air out of the frame and back into the surrounding environment. Many such server frames may be placed within a single room or data center, often in close proximity to one another to conserve floor space. In such an environment, each rack is typically open to airflow in the front and back, and enclosed on the sides. Racks may be placed in rows, having little or no separation between the side of one rack and the side of an adjacent rack, while cooling xe2x80x9caislesxe2x80x9d are provided at the front and rear of each row of racks. Cooling aisles thus facilitate airflow through the air cooled electronics rack.
As previously noted, when an air cooled system is placed in an environment having a specified ambient air temperature, increases in system power dissipation require increased airflow to maintain a desired device temperature. Increased airflow may be accomplished through the use of more powerful air moving devices, or by increasing the rotational speed (RPM) of an existing air moving device. There are disadvantages and limitations to this approach, however.
As system level power dissipation increases, so does the total quantity of heat exhausted from the rack into the ambient. Assuming that desired chip temperatures can be maintained merely by increased airflow, increases in system level power dissipation place additional burdens upon customers"" room air conditioning systems, by increasing the heat loads these systems must handle. The problem is exacerbated in server farms, or installations having many electronics racks in close proximity. Room air conditioning may therefore impose a practical limit on the total amount of heat removable from a set of electronics racks. Furthermore, as additional heat is exhausted into the ambient, neighboring racks may become increasingly susceptible to increased inlet air temperatures, due to increases in ambient temperature or to heated exhaust air from one rack xe2x80x9cleakingxe2x80x9d into the inlet of a neighboring rack.
Two additional disadvantages may be experienced when increased system level heat loads are cooled by simply increasing airflow. First, as previously noted, airflow may be increased through the use of a more powerful air moving device, or by increasing the rotational speed of an existing air moving device. In either case, the acoustic noise produced by the air moving devices is likely to increase. Increased noise levels may surpass acceptable acoustic limits, especially when many air moving devices are used in each rack system. Second, since each rack system provides air inlets and outlets in the front and back of each rack, respectively, traditional closed or solid system covers may not be utilized on the front and back of the rack system. The air inlet and outlet openings impair effective acoustic insulation and electromagnetic shielding of the rack systems.
For the foregoing reasons, therefore, there is a need in the art for an auxiliary cooling system for use with air cooled electronic rack systems.
The shortcomings of the prior art are overcome, and additional advantages realized, through the provision of a system and method for air cooling electronics systems by using a water to air heat exchanger to cool air entering the system, and to further remove a portion of the heat produced by the electronics.
The invention includes, in one aspect, a frame having an air inlet and an air outlet, at least one electronics drawer within the frame, at least one air moving device within the frame, where the at least one air moving device is capable of causing air to flow from the air inlet, across the electronics drawer, and to the air outlet, and a heat exchanger located at the air inlet, where the heat exchanger is capable of cooling incoming air to a temperature below that of the ambient.
In another aspect, the invention includes a method of cooling an electronics system including causing air to enter the electronics system, providing a first heat exchanger to cool the incoming air to a temperature below ambient temperature, and causing air exiting the first heat exchanger to flow through the electronics system.
In an enhanced aspect, the present invention includes a frame having an air inlet and an air outlet, a plurality of electronics drawers within the frame, a plurality of air moving devices within the frame, where the air moving devices are capable of causing air to flow from the inlet, across the electronics drawers, and to the outlet, an inlet cover pivotally mounted to the frame at the air inlet, the inlet cover having louvers to direct incoming airflow, an inlet heat exchanger integrated into the inlet cover, where the inlet heat exchanger is capable of cooling air entering the frame below ambient temperature and is further capable of pivoting as a single unit along with the inlet cover, where the inlet cover, louvers, and inlet heat exchanger provide acoustic insulation and electromagnetic shielding.
It is therefore an object of the present invention to provide a system and method of air cooling electronics systems by using a liquid to air heat exchanger to cool incoming air to a temperature below ambient temperature.
It is a further object of the present invention to reduce the cooling burden placed on room air conditioning systems by transferring at least a portion of the heat dissipated by the electronics system to a cooling fluid.
It is a further object of the present invention to provide convenient access to electronics drawers within electronics systems, by providing movable heat exchangers.
It is yet another object of the present invention to provide cooled electronics systems that are easily introduced into typical data center environments.
The recitation herein of a list of desirable objects which are met by various embodiments of the present invention is not meant to imply or suggest that any or all of these objects are present as essential features, either individually or collectively, in the most general embodiment of the present invention or in any of its more specific embodiments.
Additional features and advantages are realized through the teachings of the present invention. Other embodiments, features, and aspects of the present invention are described in detail herein and are considered part of the claimed invention.